And in April Colon was summoned to the monarchs’ court once more. The monarchs received him in the Alhambra itself, in a chamber the Moors had called the Hall of the Mexuar, a room in the oldest part of the palace where the daylight was filtered through the stained glass of a lantern roof. In this architectural triumph of a vanquished people, amid rooms inscribed with Moorish slogans - Wa la ghalib illa Allah, there is no conqueror but Allah - Colon’s contract documents were sealed. He was given a letter from Fernando and Isabel to the Great Khan of the Mongols. And as a final flourish Colon begged the monarchs to devote all the treasure raised by his expedition to the reconquest of Jerusalem.

But Colon would not be able to sail from Seville or Malaga, for those great ports were choked with fleeing Jews.

He headed for little Palos on the Tinto estuary instead; Colon was glad to honour the town where he had found such support from the brothers of La Rabida. But on the road Colon was caught up in great chains of refugees, more Jews, struggling to get to the coast. Some of them carried shards of the shattered tombstones of their ancestors. They were dusty, exhausted, ill; some helpless mothers even gave birth on the road. But their rabbis made the women sing and play tambourines to raise the people’s spirits. And even when Colon reached Palos he had trouble securing ships, for all the masters were busy with the urgent task of transporting Jews.

Just at this moment when it was preparing to reach out across the world, Spain was cleansing itself.

Geoffrey said, ‘What a terrible mistake the expulsion could prove to be! Torquemada’s bitter heart may be brimming. But Spain is stripping herself of her most industrious citizens - of a whole class of bankers and moneylenders, artists and administrators; no hidalgo or caballero would lower himself to such work. Just as she is on the verge of empire, Spain is ridding herself of the talents she needs to run it. Ha!

‘And the Moors will surely follow the Jews out of Spain sooner or later, whatever promises the monarchs have made. What will become of the Moors I don’t know, for though their ancestors came from the deserts of Africa and Araby, they don’t belong there now any more than you or I would have a place in the German forests of our own forebears. Perhaps they will simply dissipate, a vanished people, leaving behind their palaces and books, and the future will wonder that a Muslim nation once flourished in western Europe . . .’